Dental articles like crown and bridges can be produced by different processes using different materials. In the last couple of years a lot of efforts were spent in developing processes for producing dental articles based on ceramic materials. Those dental articles typically comprise two sections, a base section or support structure which provides the necessary strength and a cover section or veneer which should contribute to improving the aesthetic appearance of the final dental article.
The veneering of the support structure is typically done manually (e.g. by layering of ceramic slurries).
Alternatively, the veneering can be done by making a mould and using a pressing technique. Such a process is described e.g. in US 2006/0099552 (van der Zel et al.).
Another approach for producing ceramic dental article is using milling techniques.
WO 2008/144342 (3M) for example relates i.a. to a method of making a facing for a dental restoration comprising the step of providing a facing precursor from which the facing is obtainable and wherein the facing precursor is comprised of an open-celled material. The method provides for efficient manufacturing of dental restorations.
Other references try to produce dental articles applying solid free-forming fabrication methods, however without focusing on dental veneers.
U.S. Pat. No. 5,902,441 (Bredt et al.) focuses on a method of three dimensional printing an article using adhesive particulate mixtures.
U.S. Pat. No. 6,322,728 (Brodkin et al.) deals with mass production of dental restorations by solid free-form fabrication methods.
U.S. Pat. No. 6,955,776 (Feenstra) describes a method for fabricating a functional dental element such as a crown using a three-dimensional printing technique.
U.S. Pat. No. 7,086,863 (Van der Zel) relates to a method for production of an artificial tooth comprising a base layer and at least one cover layer. The method comprises steps like establishing the available outer shape and dimensions for the finished artificial tooth, acquiring an image, determining variations in the appearance determining properties of the cover layer, constructing the base layer and applying the cover layer over the base layer.
U.S. Pat. No. 6,648,645 (MacDougald et al.) relates to a process for fabricating a dental material comprising mixing ceramic powder and one or more media together to form a putty, applying the putty to a model to conform to the shape of the model and to form a ceramic core material; and sintering the model with the putty thereon for a certain period of time.
US 2006/0131770 (Dierkers et al.) describes a process for the production of a dental model with the steps: providing a fluid, solidifiable material and an electrically conductive substance, producing the dental model by rapid prototyping so that the dental model produced is electrically conductive.
WO 2009/073498 (3M IPC) deals with a method comprising positioning a stem in a base, rotating the base and depositing a material on the stem under computer control to create a workpiece.